January 11, 2012

Marijuana Much Less Dangerous Than Cigarettes

by editor

A new study published this week in the Journal of the American Medical Association suggests that the lung capacity of marijuana smokers is not diminished by regular toking, even among those who smoked once or twice a week, reports Genevra Pittman for Reuters Health. This disproves one of the major concerns about marijuana - that smoking it must be just as risky as lighting up a cigarette.

Only those who smoked 20 or more joints a month saw a negative impact on the pulmonary system. However that level of marijuana use is unusual, researchers said. They suggest that marijuana smoke doesn´t affect lung function the way tobacco does simply because people don´t smoke as much marijuana as they do tobacco.

“Previous studies have had mixed results,” Dr. Stefan Kertesz, from the University of Alabama at Birmingham explained to Pittman. “Some have hinted at an increase in lung air flow rates and lung volume (with marijuana smoking), and others have not found that. Others have found hints of harm.”

While marijuana smoke has a lot of the same toxins as cigarette smoke, he added, people who use pot tend to smoke fewer joints each day than tobacco users smoke cigarettes. That and the method of inhaling may offer some relative lung protection, researchers have proposed.

Doctors and patients who are considering using marijuana for medical care to ease pain and nausea, can breathe a little easier, suggested Dr. Mark Pletcher, a UCSF epidemiologist and lead author of the study.

But that´s not to say that Pletcher or his colleagues are ready to give the all clear to anyone who wants to smoke pot, reports Erin Allday of the San Francisco Chronicle.

“This study shouldn´t be interpreted as marijuana is totally harmless,” said Dr. Stephen Sidney, a study author with Kaiser Northern California´s division of research in Oakland. “We don´t see marijuana having a big impact on lung function or lung disease. But it doesn´t mitigate the fact that we have an issue with marijuana, at least in terms of dependence on it.”

Smoking cigarettes has such dramatic, long-term health consequences - including emphysema and lung cancer - that doctors have long assumed that marijuana smoking, too, must be detrimental.

“This study is challenging the preconceived notions we´ve had for some time about the dangers of smoking cannabis and the similarities to smoking tobacco,” explained Amanda Reiman, a UC Berkeley lecturer and director of research at the Berkeley Patients Group, a medical marijuana dispensary, to Allday.

“No one would ever claim that drinking water has the same effect as drinking vodka, even though they´re both liquids and you´re ingesting them the same way,” she explained. “But for some reason we have assumed that because we know the negative outcomes with cigarettes, inhaling any plant material is going to have the same outcomes.

The study lumped together all types of inhaled marijuana use, meaning researchers did not differentiate among those who smoked joints or pipes or any other implement.